There is one Easter egg that is very easy to spot in Black Mirror: Bandersnatch. The computer game "Metl Hedd," which features a robotic creature, is the best-seller at Tuckersoft, the company that serves as the backdrop for the Netflix interactive film. Bandersnatch, a stand-alone offering of Charlie Brooker's sci-fi anthology series, dropped on Dec. 28 and launched the streaming giant into the new way of TV storytelling.

The "Metl Hedd" reference is a clear nod to the Black Mirror season four episode "Metalhead." The black-and-white survival story featured Maxine Peake running from a robotic killer dog. Brooker is famous for laying Easter eggs within Black Mirror episodes that connect the stories to the larger show universe. But David Slade, who directed both the episode "Metalhead" and the film Bandersnatch actually fought the callout.

"We were looking for games that Colin Ritman [played by Will Poulter] had written and 'Metalhead' seemed like it would be a good one to do because the chase scene is kind of a platform game. [Season four episode] 'Nosedive' became the falling game, a real game. But David thought the 'Metalhead' egg was too obvious," Russell McLean, who produced Bandersnatch, tells THR. Slade adds, "I didn’t really see the need for it, but that’s just me."

Indeed, the "Nosedive" game — which is titled "Nohzdyve" in Bandersnatch — is now a real game that can be played, thanks to savvy viewers decoding the post-credits Easter egg left for them by Brooker. An uncovered Tuckersoft site lets viewers play the game, if they have a ZX Spectrum emulator.

The secret Tuckersoft site actually contains several references to other Black Mirror episodes, including "Metalhead" and season two's "White Bear," which is where viewers will recall they first saw the Bandersnatch symbol, the branching narrative glyph that consumes Stefan (Fionn Whitehead) as he develops his 'Bandersnatch' computer game in the meta story. (Another Tuckersoft site leads visitors to Netflix job postings.)

Tuckersoft, as a matter of fact, holds a lot of weight within the Black Mirror universe. Though the company dismantles in one of the main endings of Bandersnatch, it will eventually be reborn as TCKR, the tech company that has been referenced in a handful of other Black Mirror episodes, including "San Junipero," "Playtest," and "Black Museum." The season three episode "Playtest," a video game-themed horror starring Wyatt Russell, even foreshadowed Bandersnatch by including a review for the game on a magazine cover.

"Yes, Tuckersoft may have become TCKR, in the future," says Slade of the company led by Mohan Thakur (Asim Chaudhry) being the first iteration, which makes Bandersnatch an origin story of sorts. "This would be the time that TCKR was started, in ’84 in Britain."

Brooker has always included Easter eggs for savvy fans, but the most recent fourth season was an explosion of references. Bandersnatch continued the trend. The hospital of Stefan's psychiatrist is called Saint Juniper, the same one featured in the Emmy-winning "San Junipero." The past story clippings and future scrolls of breaking news that appear in Bandersnatch feature stories relating to the Space Fleet from "USS Callister," Prime Minister Michael Callow from "The National Anthem," "The Waldo Moment's" Liam Monroe, the dating program for "Hang the DJ," the talent show of "Fifteen Million Merits," the memory recall device in "Crocodile" and the pollinator drones from "Hated in the Nation."

"Well, I think you will find — as Colin Ritman explained — that there are many, many realities and universes, so I guess this probably opens up one of them!" Brooker tells THR of Bandersnatch's potential impact on the series. "With the Easter eggs and with the wide mythology surrounding the show, it’s useful for us to think of it that it's a nice nod for superfans who notice that Tuckersoft becomes TCKR. It can function like that."

Brooker, who wrote Bandersnatch and every Black Mirror episode, then goes on to clarify that the Easter eggs, no matter how big or small, are not meant to pull a viewer out of a specific story. And he doesn't let it control the creative process.

"With any of our episodes, you can watch them in any order and you don’t need to know any of this stuff. It’s there as an extra bit of texture for fans of the show," Brooker says. "There are lots of variants of other episodes within Bandersnatch. But I don’t have an atlas to the Black Mirror universe. I think that would start restricting what we can do. We always prefer to go in and include a nod to something else if it’s logical and fun, but we don’t like to be bound by that."

Black Mirror executive producer Annabel Jones adds that the Easter eggs, like the multiple endings in Bandersnatch, are supposed to be satisfying additives to the story. "One of the prominent images is the glyph. The branching narrative device illustration was something we used in the early episode 'White Bear' where our protagonist was having to relive day after day of the same awful experience," Jones, Brooker's producing partner, tells THR. "So you lean on that thematically and it hopefully becomes satisfying to the people who notice it and to the people who don’t, then it’s not a factor."

As viewers continue to uncover more of the Bandersnatch endings, it eventually becomes clear that Colin Ritman is a trans-dimensional character — someone who lives across more than one reality. In several branches of the story, Colin has a residual memory he is able to access without explanation.

"Colin was the most challenging because you have three different scenes and you’re going through the same three scenes but what the character knows is different. So how do we do that? How does that make sense?" explains Slade of the complicated filmmaking process. "I had a conversation with Will [Poulter] where I said, 'He knows. He knows everything. That's the best advice I can give you. How he knows, why he knows? He just knows.' At the end of the shoot, Will said that was the one thing he kept coming back to, was that he knows."

The fifth season of Black Mirror is set to arrive in 2019. Whether or not that means Colin could show up in future Black Mirror episodes is a question Slade leaves up to Brooker to answer. Even if viewers got the option for Stefan to "Kill Colin" (a choice point that only arises if viewer's made certain choices prior), Brooker points out that Colin was intentionally laid back about meeting his apparent death in Bandersnatch.

"Yes, ostensibly, he could go on forever, because he’s both dead and not dead," Brooker clarifies. "Colin popped up as a character and then I kept writing more and more for him because I was really enjoying him. I like the idea of that. He could show up anywhere. We should be like George Lucas and go back and insert him into episodes we’ve already done. I could see him popping up in 'San Junipero' or running around in 'White Bear.'"

But Slade does have a strong opinion on whether or not the dystopian future they captured in "Metalhead" still stands. Since Colin developed the game in 1984, could the season four episode now be looked at through a different lens: were Black Mirror viewers being trapped inside a computer-generated world?

"That’s a really good question," says Slade. "I think 'Metalhead' is something that’s going to happen in the future. I’m sure all these options are open to you, but I think that’s a very definite thing that will happen in the future. And I think things will happen after that, too. I don’t think 'Metalhead' is a simulation."

Knowing how Brooker expands the show universe with each Black Mirror episode or film, Slade and McLean say they did have conversations with the creator and writer about the hidden meanings of Bandersnatch.

"There is a debate in the Reddit community about whether it’s all in the same universe. It all comes out of Charlie and Annabel’s minds, so in that sense it’s all the same universe. But we never talked about: how do we fit the story into this universe?" says McLean. "Our focus is to make Bandersnatch work. And then there are references to other things."

Slade then adds, "But I think Charlie is building that jigsaw puzzle. We had conversations where we said, 'If there is real meaning, we need to know.' Just the form of this means people will really scrutinize it, so if there is real meaning, it needs to be real. The Tucker thing was definitely something, that was a definite thing."